The invention includes embodiments that relate to a method of bonding superalloys. More particularly, the invention relates to a semi-solid method of bonding superalloys.
Superalloy components are commonly used in various applications, including, for example, in aircraft engine, gas turbine, and marine turbine industries. Generally, the quality of the superalloy components is imperative to their successful function. To achieve the requisite quality products, even very large superalloy components (e.g., first stage buckets of gas turbines) are often cast so as to avoid joining (bonding) components wherever possible. However, such large superalloy components typically suffer from low casting yield due to the size, complex shape, and/or presence of core. Even for smaller components, casting a single component can be less than ideal due to, for example, complex shapes required of the component.
Segmenting superalloy components into smaller multiple subcomponents enables reducing the size of subcomponents, simplifying the shape, and/or eliminating the core, thereby allowing for improved casting yield. However, thus far, prior art focusing on joining processes, including welding and brazing, for superalloys has failed to produce mechanically sound joints. When superalloy components are joined, the joint typically possesses inferior mechanical properties (lower tensile strength, shorter creep and fatigue life, lower ductility) due to discontinuity of chemistry and/or microstructure across the joint. The same drawbacks have impacted the ability to obtain hybrid components comprising different alloys, and have plagued the art of repair processes, which seek to replace damaged portion(s) of superalloy components.
Thus, a need exists for an improved method of bonding superalloys that allows for joining subcomponents, preferably in higher-yield processes while maintaining high quality mechanical properties.
While certain aspects of conventional technologies have been discussed to facilitate disclosure of the invention, Applicants in no way disclaim these technical aspects, and it is contemplated that the claimed invention may encompass one or more of the conventional technical aspects discussed herein.
In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was, at the priority date, publicly available, known to the public, part of common general knowledge, or otherwise constitutes prior art under the applicable statutory provisions; or is known to be relevant to an attempt to solve any problem with which this specification is concerned.